Heidi Loughlin, 32, discovered she had a rare and aggressive form of breast cancer after falling pregnant with her third child.

She was diagnosed with inflammatory breast cancer, which typically has a prognosis of between two and five years, in September after noticing a rash on her breast while breastfeeding her baby son Tait.

Doctors gave her the option of terminating the pregnancy so she could begin aggressive chemotherapy.

But she decided to keep her baby and begin a less aggressive form of chemotherapy treatment so Tait and her other son Noah, aged two, would not lose their mother.

After her initial treatment failed doctors recommended she undertakes intensive chemotherapy which could save her life but put her unborn baby's health at risk.

Ms Louglin, a Met Police officer from Portishead, North Somerset has decided that her only chance of survival is to give birth on Friday - at 12 weeks early.

She can then immediately start an intensive form of treatment with the drug Herceptin and hope her baby is strong enough to survive.

Initially Ms Loughlin, who has been with her partner Keith Smith for seven years, decided to have a less dangerous form of chemotherapy to give her baby the best chance of survival.

Writing on her blog, Ms Loughlin said: "This wasn't meant to be the post I was going to write.

"It's all change people, all change. It's not the end of the line but there are engineering works here and we need to change trains and pretty quickly.

"I had a follow up Oncology appointment last week and we have concluded that the treatment isn't working to a satisfactory level.

"Now ordinarily we would now switch treatments immediately and thus I'd be having the next stuff along with a miracle drug called Herceptin.

"However, me being me, I don't like to make things easy for people and we have this little matter of the baby. Babies and Herceptin don't mix.

"This means the baby will be 12 weeks early. This is absolutely terrifying.

"Also what is terrifying is that if I stay pregnant until New Year's Eve as originally planned then there's a pretty good chance I've missed my window of potential cure.

"Realistically I've got to make a decision that encompasses everyone. I absolutely need to be here for my children.

"But I'm scared to my core about a baby born so early. I am also scared that I may not get through this. Mostly I'm scared of doing the wrong thing."

Ms Loughlin is currently recording her cancer battle through her popular, humorous and very frank blog Storm In A Tit Cup.